Choose the right octane. For most cars, the recommended gas is regular octane. Using a higher octane gas than the manufacturer recommends offers no benefit, and it costs you at the pump. Unless your engine is knocking, buying higher octane gas is a waste of money.
Stay away from gas-savings gadgets. Be skeptical about any gadget promising to improve your mileage. The Environmental Protection Agency has tested more than 100 such devices -- including "mixture enhancers" and fuel line magnets -- and has found that very few provided any benefits. Those that worked provided only a slight improvement. Some can even damage your engine.
Stay within the speed limit. Gas mileage decreases rapidly at speeds above 60 mph.
Avoid unnecessary idling. It wastes fuel, costs you money and pollutes the air. Turn off the engine if you anticipate a wait.
Stop and start gently. You can improve in-town gas mileage by up to 5 percent by driving gently.
Use overdrive and cruise control. They improve fuel economy when you're driving on the highway.
Inflate your tires. Keeping your tires properly inflated and aligned can increase gas mileage up to 3 percent.
Keep your engine tuned. Tuning your engine can increase gas mileage by an average of 4 percent.
Change your oil. Clean oil reduces wear caused by friction between moving parts and removes harmful substances from the engine. Motor oil that says "energy conserving" on the performance symbol of the American Petroleum Institute contains friction-reducing additives that can improve fuel economy.
Replace air filters regularly. Replacing clogged filters can increase gas mileage up to 10 percent.
Lose the junk in your trunk. An extra 100 pounds in the trunk can reduce fuel economy by up to 2 percent. Removing nonessential stuff can save you at the pump.
Combine errands. Several short trips taken from a cold start can use twice as much fuel as one trip covering the same distance when the engine is warm.
Consider carpooling. Many cities make it even easier by matching up commuters.
Bus it, bike it or hoof it. Why not leave your car at home and consider public transportation, a bike ride or a stroll across town?
With reports from Charles B. Herman.